Prevention of contamination and cross-contamination have long been matters of primary concern in the dental/medical field. Where handpiece instruments must be reused on successive patients care is required as are certain anti-microbial steps to prevent transmission of virally or bacterially caused infections from one patient to another. An equal concern is to obviate transmission of such infections from or to the health care provider.
An increasing awareness of the potential for the spread of highly contagious viral and bacterial diseases has led to further emphasis being placed on infection control in the dental operatory. The American Dental Association (ADA) and the Centers for Disease Control (CDC) have been instrumental in publishing guidelines intended to reduce the opportunity for disease transmission during the practice of dentistry. These recommendations support the use of protective apparel by dental professionals whose ordinary duties require hands-on contact with patient body fluids, instrumentation and materials used in dental procedures. It is also recommended that non-disposable instrumentation and materials used in the dental operatory be at least disinfected.
"Sterilization" is the process by which micro-organisms are destroyed, including viruses, bacteria, fungi, and spores. Sterilization may be achieved by (1) steam under pressure (autoclave), (2) prolonged dry heat, (3) chemical vapor, (4) ethylene oxide gas, and (5) submersion in chemical sterilants. "Disinfection" is less lethal to microbials than sterilization and typically requires application of a chemical registered with the EPA.
The ADA has recommended that high-quality disposable medical gloves, a surgical mask covering the nose and mouth, and protective eye wear be worn by dental professionals due to constant exposure to patient-contaminated coolant aerosols associated with high speed handpieces as well as exudates of blood, pus, saliva, oral tissue, and decayed tooth material. It is recommended that the dental assistant and the hygienist wear disposable medical gloves. Hand washing and use of oral rinses, a rubber dam, and a saliva evacuation system are also encouraged. Training each health care provider is also important.
The ADA has also recommended autoclaving for instruments and non-disposable materials that are able to withstand the high heat of an autoclave cycle. Non-autoclavable instrumentation and materials should be chemically disinfected with a properly diluted, and freshly prepared disinfectant solution according to the manufacturer's instructions. Large equipment in the dentists' office should be "wiped down" routinely with a suitable anti-microbial solution. Significantly, hepatitis B and HIV are heat sensitive viruses, which are essentially rendered non-contagious by short-term autoclaving.
Except for a suggestion of wiping the handpiece routinely with recommended "wipe down" disinfectants, there is, to our knowledge, no other ADA recommended technique for the disinfection of heat intolerant handpieces between patients. And yet, the handpiece is subjected to the exact same patient-contaminated coolant aerosols and exudates as are the dentist's hands, nose and mouth, and eyes. The handpiece is not only subjected to the contaminated material cast onto it by the coolant aerosol and the mechanical rotation of the tool, but also contaminants transferred to the handpiece by the dentist's glove. Thus, a potential source of cross-contamination from patient to patient exists through the handpieces and microbial contaminants surviving the disinfectant wipe are likely to be transferred to subsequent patients on the newly-donned gloves of the dental professional. Handpieces in today's technology have turbine blades which spin at more or less 500,000 revolutions per minute under air pressure. When the air and/or water pressures are turned off, a vacuum is created which may suck blood, saliva, and serum into the handpiece as a potential source for cross-contamination.
Transmission of microbials through the air in dental offices is also a matter of substantial concern.
Diseases of concern comprise the common cold, hepatitis B (HBV), non-A/non-B hepatitis, influenza, measles (German and rubeola), tuberculosis, staphylococcus, and streptococcus, herpes infections including chicken pox, infectious mononucleosis, epstein bar, herpetic whirlow, herpetic conjunctivitis, and AIDS (the HIV [human immunodeficiency virus] virus).
While it is clear that autoclave sterilization is the anti-microbial treatment of choice, the cost of buying, operating, and maintaining autoclave equipment is high and more handpieces need to be purchased and utilized where handpiece autoclaving occurs between each patient. Also, as stated above, not all handpieces can withstand the heat of autoclaving. Thus, many doctors today, however, appear to find it impractical to sterilize handpieces after each patient use because of possible damage to the devices and the necessary burdensome financial investment in multiple handpieces required to maintain an acceptable instrument flow. Nevertheless, the CDC currently recommends heat treatment of all handpieces using also acceptable methods which assure internal and external sterility between patients.